Cardiogenic Shock Flashcards
CARDIOGENIC SHOCK
Is an acute state of decreased CO resulting in inadequate tissue perfusion, despite adequate circulating volume. Cardiogenic shock is the leading cause of in-hospital death in patients with acute myocardial infarction (AMI)
What strategies have improved early revascularization in cardiogenic shock patients with acute ischemia?
PCI or coronary artery bypass surgery improved survival of cardiogenic shock patients with acute ischemia compared to medical therapy alone.
Most Common Cause of Cardiogenic Shock
The most common cause of cardiogenic shock is extensive myocardial infarction that depresses myocardial contractility
Cardiogenic Shock is primarily _________ failure What happens to CO, systolic bp, vital organ perfusion, diastolic pressure, coronary artery perfusion?
“Pump failure,” Reduced cardiac output. SBP drops d/t poor cardiac output vital organ perfusion is limited. Absent a rise in systemic vascular resistance, the DBP also drops -resulting in coronary artery hypoperfusion. ((This creates a cycle of worsening myocardial ischemia and pump dysfunction, and eventual decompensation.))
Cardiogenic Schock Physical Exam
PHYSICAL EXAMINATION -Characterized by hypoperfusion; this is not always accompanied by hypotension. -SBP is usally <90, although it can be higher with preexisting hypertension. -Pulse Pressure <20 mm Hg is another finding if systemic resistance has not plummeted -Sinus tachycardia is common unless the patient is on medications that block a tachycardic response. -Unless the patient has advanced to the stage of respiratory fatigue or agonal respirations, tachypnea is common. -Lungs: demonstrates rales due to the presence of pulmonary edema, except in cases of isolated right-sided failure. -JVD and a positive hepatojugular reflex are usually present -Patients are usually pale or cyanotic and may have cool skin and mottled extremities or other signs of hypoperfusion. -Peripheral edema suggests preexisting heart failure. -Diaphoresis indicates activation of the sympathetic nervous system. Cerebral hypoperfusion may result in altered mental status, and renal hypoperfusion may decrease urine output.
Cardiogenic Shock Heart Sound
-If PMI is laterally shifted and diffuse from cardiac remodeling and enlargement, you can assume this pt has had long-standing cardiac disease with acute decompensation -About 10% of cardiogenic shock after AMI is caused by mechanical complications.
-A new murmur may be the only physical exam finding of mechanical catastrophe; carefully seek any loud or new systolic murmurs.
-Acute mitral regurgitation can occur from chordae tendineae rupture or papillary muscle dysfunction, accompanied by a soft holosystolic murmur at the apex radiating to the axilla with rales.
- With papillary muscle dysfunction, the murmur starts with the first heart sound but terminates before the second.
- An acute ventral septal defect is associated with a new loud holosystolic left parasternal murmur, often with a palpable thrill, that decreases in intensity as the intraventricular pressures equalize.
- Acute aortic insufficiency is characterized by a soft diastolic murmur and a softer S1 sound.
BNP Level in Cardiogenic Shock
The level of serum B-type natriuretic peptide (BNP) is an indicator of left ventricular dysfunction. Because of its high negative predictive value, a normal BNP level (<100 picograms/mL) eliminates cardiogenic shock as the cause of hypoperfusion
NL BNP = CARDIOGENIC SHOCK IS NOT CAUSING HYPOPERFUSION
ECG in Cardiogenic Shock
-Obvi helps detect ischemia or STEMI
*** Super important to assess for RV invoelment bc RV infarction is a/w increased risk for cardiogenic shock and death
- RV infarction is best evaluated by obtaining right-sided ECG leads (usually V4R and V5R)
- RV infarction complicating inferior myocardial infarction is detected by ST elevation in lead V1 with depression in V2.
CXR in Cardiogenic Shock
Chest x-ray typically shows pulmonary congestion or edema, alveolar infiltrates, and pleural effusion.
Echo in Cardiogenic Shock
Bedside Echocardiography
- Assess that IVC to determine volume status and estimate right atrial pressure
- A subcostal four-chamber view is helpful to visualize pericardial effusion and identify cardiac tamponade.
- When tamponade is present, there is a pericardial effusion with associated dilation of the IVC and diastolic collapse of the RV with systolic collapse of the right atrium.
- -*When cardiac rupture has occurred, there may be a visible clot in the pericardial space.
- Subcostal, parasternal, and apical views together can help estimate EF and cardiac contractility.
- An aortic root measurement greater than 3 cm is concerning for ascending aortic dissection, especially when associated with a pericardial effusion.
- Also assess mitral valve morphology and motion. Apical four-chamber views are helpful for evaluating chamber size.
- In cases of acute right heart failure due to ischemia, the RV will be dilated and the left ventricle (LV) will appear to be smaller than expected due to low filling pressures.
- In left heart failure there will be dilation of the LV secondary to decreased cardiac output and increased filling pressure.
Hemodynamics in Cardiogenic Shcok
Hemodynamic Monitoring
- Patients in cardiogenic shock typically have low cardiac index (<2.2 L/min/m2) and elevated LV end-diastolic pressure (pulmonary artery occlusion pressure >18 mm Hg).
- Invasive hemodynamic monitoring with a pulmonary artery catheter can provide data and guide treatment but is unavailable in most EDs.
- Central venous pressure measurements can help guide fluid resuscitation, with the trend in venous pressures being more important than absolute values. Most patients will require continuous blood pressure monitoring, often with an indwelling catheter.
ASPIRIN/Nitro
In AMI, give aspirin early (if not already taking long term) unless there is an absolute contraindication.32
If blood pressure is >90 mm Hg systolic, chest pain may be relieved by careful use of IV nitroglycerin or morphine. Do not use a-blockers in patients with myocardial infarction in cardiogenic shock or who are at risk for cardiogenic shock (Table 50-1).32 Withhold angiotensin-converting enzyme inhibitors or other vasodilators.
Fluid in Cardiogenic Shock
HYPOTENSION
-Give crystalloid fluid boluses (250 to 500 cc) for an RV infarct with hypotension, if pulmonary congestion is absent. If there is no improvement with the fluid bolus or if pulmonary congestion develops, vasopressors or inotropes are indicated
What are the inotropes used in Cardiogenic Shock?
DOB
DOPE
NOR
EPI
MILRI
DOB
Dobutamine2–5 micrograms/kg/min, titrated up to 20 micrograms/kg/minInotrope and potential vasodilator; lowers blood pressure; give as individual agent as long as systolic blood pressure (SBP) ≥90. Can use with dopamine.
